Investigative Processes

Forensic notes

Just as car needs fuel to run, criminal laboratories also need ______ to run

evidence

Evidence can be what _____ or _____ a criminal case

makes, breaks

Evidence can be used to convict, exonerate or prove a defendant to be ___ guilty of an accused crime

not

Before evidence can be used, its presence must be _______ at the crime scene

recognized

Forensic Science begins at the _____ _____

crime scene

If the investigator cannot ______ evidence or cannot properly preserve it for laboratory examination, it is of no use

recognize, preserve

With proper training, police agencies and investigators can _____ competent performance at crime scenes

ensure

Who is at the crime scene?

Police or District Attorney (DA may be present to issue warrant)

Crime scene investigators (document scene in detail and collect evidence

Medical examiners (coroners, determine COD)

Detectives (look for leads, interview)

Specialists (toxicology, psycologists)

Chain of Custody

The chronological documentation or paper trail that records the sequence of custody, control, transfer, analysis, and disposition of physical evidence or electronic evidence is known as the…….

What are the steps that crime scene investigators follow

Securing the Scene

Separating witnesses

Scanning the Scene

Seeing the Scene

Sketching the Scene

Searching the Scene

Securing and Collecting Evidence

1. Securing the Scene (Who? What? When? Why? How?)

Who: The First Responder

What: Setting clear boundaries around a crime scene to protect evidence. secure if someone is injured or suspect is on site. Log who’s in & out

When: immediately as the responder arrives on the scene

Why: protect evidence from destruction/ contamination and to protect the public from danger

How: using physical barriers and controlling all accessible angles as well as using yellow caution tape

2. Separating Witnesses (Who? What? When? Why? How?)

Who: first responding officers & detectives or crime investigators handle separation. All individuals who witness the event, potential suspects, or bystanders are subject to separation

What: keeping witnesses physically apart so they cannot change stories. Conduct individual questioning

When: Immediately after securing the scene and prioritizing medical safety. Before any discussion can happen between witnesses

Why: avoid memory contamination, prevent conspiracy, and ensure accurate individual testimonies.

How: officers escort individuals to separate locations immediately. Investigators ask baseline questions

3. Scanning the Scene

Who: Crime scene investigators, forensic technicians, lead investigators officers.

What: 3D photos. Photos. Conducting a preliminary survey of the scene to identify evidence and potential paths of investigation.

When: right after securing the scene and separating witnesses.

Why: To develop an initial understanding of the crime and determine a strategy for evidence collection.

How: By carefully observing the scene, noting key locations, and taking initial photographs. Do a walkthrough.

4. Seeing the Scene (Who? What? When? Why? How?)

Who: Forensic investigators and photographers.

What: Take photos of the overall scene and close ups with items using evidence markers for size reference. Observing the crime scene for additional evidence and context.

When: After initial scanning and securing the scene.

Why: courts can have photo evidence and measurements of objects at the scene and overall area. To gather comprehensive information and identify overlooked evidence.

How: By conducting systematic searches and using appropriate forensic techniques. Use of camera and baseline observations of the scene.

5. Sketching the Scene (Who? What? When? Why? How?)

Who: Forensic artists and crime scene investigators.

What: Creating a visual representation of the crime scene, including the location of evidence, bodies, and other relevant details.

When: After photographing the scene and before evidence is processed.

Why: To provide a clear and accurate depiction of the scene for investigative purposes and court presentations.

How: By measuring distances, using scales, and incorporating photographic evidence to create detailed sketches.

6. Searching the Scene (Who? What? When? Why? How?)

Who: Crime scene investigators and forensic teams.

What: Systematic examination of the area to locate hidden or overlooked evidence.

When: After sketching the scene and once initial evidence is collected.

Why: To uncover additional information that may be pivotal to the investigation.

How: By employing various search methods, including grid, spiral, or quadrant techniques, and using tools like metal detectors or hand-held lights.

7. Securing and Collecting evidence (Who? What? When? Why? How?)

Who: Crime scene investigators and evidence technicians.

What: The process of gathering physical evidence from the crime scene, ensuring it is properly documented and preserved.

When: Following the search of the scene and before leaving the site.

Why: To maintain the integrity of the evidence for analysis and presentation in court.

How: By using appropriate collection techniques, labeling, and packaging methods to prevent contamination.